Successful use of estolides of hydroxy-containing triglycerides as environmentally friendly, that is, biodegradable base fluids in industrial applications is contingent upon increasing the performance values as stated above. In many industrial applications these values of the estolide are too poor to be of practical use. In order to take advantage of the biodegradability of estolides, it becomes necessary to increase the performance values.
U.S. Pat. No. 844,426 (Twitchell, Feb. 19, 1907) relates to a process for manufacturing certain organic products. One of the reactants contains an alcoholic hydroxyl, of which castor oil is cited, and the other reactant is a fatty acid such as stearic and oleic acids. The reaction takes place in the presence of a catalyst described as containing a sulfa fatty acid group.
U.S. Pat. No. 2,156,737 (Priester, May 2, 1939) relates to the preparation or production of unsaturated fatty acids of the type containing two double bonds and to the preparation of an intermediate product from which said unsaturated fatty acids may be derived.
More particularly stated, this reference relates to a process for the preparation of 9,11-octadecadiene 1-acid from ricinoleic acid. The ricinoleic acid is both pure ricinoleic acid or ricinoleic acid obtained from castor oil of which the latter being obtained by the splitting up of castor oil.
U.S. Pat. No. 2,049,072 (Mikeska et al, Jul. 28, 1936) relates to the preparation of lubricants by blending with a mineral oil the product obtained by esterification of hydroxy groups in natural or synthetic fatty acids or glycerides, with special reference to castor oil, with or without subsequent stabilizations of said esterified product as by hydrogenation.
U.S. Pat. No. 2,652,410 (Cunningham et al, Sep. 15, 1953) relates to methods for reacting alpha-hydroxy acids and/or estolides with polyhydric alcohols. More particularly, this reference relates to methods for esterifying and dehydroxylating alpha-hydroxy acids and/or estolides such as are obtained by the controlled oxidation of paraffin wax.
U.S. Pat. No. 2,877,181 (Dilworth et al, Mar. 10, 1959) relates to anhydrous calcium fatty acid greases. More particularly, this reference discloses an additive that stabilizes anhydrous calcium fatty acid greases. This additive is an estolide and the estolides which act as stabilizers are intermolecular esters and polyesters of C.sub.10 to C.sub.24 hydroxy fatty acids having the general formula ##STR2## wherein R is an aliphatic hydrocarbon radical containing 1 to 21 carbon atoms, x is an integer having a value to 1 to 21 and n is an integer having a value of to about 12.
U.S. Pat. No. 4,582,715 (Volpenhein, Apr. 15, 1986) relates to alpha acrylated glycerides of the formula: ##STR3## wherein each R.sup.1 is a C.sub.10 -C.sub.14 alkyl group and wherein each R.sup.2 is a C.sub.14 -C.sub.16 aliphatic group.